ci: run nested plugin modules; align nested go versions

Author: Cod-e-Codes

.github/workflows/go.yml

@@ -38,6 +38,24 @@ jobs:
             go vet ./...
           fi
 
+      # Nested modules are not part of root `go test ./...` / `go build ./...` (separate go.mod).
+      - name: Nested Go modules (plugin/sdk, plugin/examples/echo)
+        run: |
+          set -euo pipefail
+          for dir in plugin/sdk plugin/examples/echo; do
+            echo "::group::$dir"
+            (cd "$dir" && go mod tidy && go build ./... && go test -race ./... && go vet ./...)
+            echo "::endgroup::"
+          done
+          LINT="$(go env GOPATH)/bin/golangci-lint"
+          if [ -x "$LINT" ]; then
+            for dir in plugin/sdk plugin/examples/echo; do
+              echo "::group::lint $dir"
+              (cd "$dir" && "$LINT" run ./...)
+              echo "::endgroup::"
+            done
+          fi
+
   database-smoke:
     runs-on: ubuntu-latest
     services:

TESTING.md

@@ -329,7 +329,7 @@ Statement percentages below are from the merged profile (`go tool cover -func=co
 
 The test suite is designed to run in CI/CD environments:
 
-- **Default job** (`.github/workflows/go.yml` `build`): `go test -race ./...` on Ubuntu (SQLite only for DB tests; CI DB smoke tests skip without env).
+- **Default job** (`.github/workflows/go.yml` `build`): `go test -race ./...` on Ubuntu (SQLite only for DB tests; CI DB smoke tests skip without env), then **`plugin/sdk`** and **`plugin/examples/echo`** each run `go mod tidy`, `go build ./...`, `go test -race ./...`, `go vet ./...`, and **`golangci-lint run ./...`** when the linter was installed for the root job (nested modules use their own `go.mod` and are not included in root `./...`).
 - **Database smoke job** (`database-smoke`): Postgres 16 and MySQL 8 services, then `go test -race ./server -run 'Test(Postgres|MySQL)InitDBAndSchemaSmoke'` with `MARCHAT_CI_POSTGRES_URL` / `MARCHAT_CI_MYSQL_URL` set.
 - **Parallel Safe**: Standard tests avoid shared mutable global state; subprocess tests serialize via their own `go run` invocations.
 - **Deterministic**: Doctor subprocess tests set `MARCHAT_DOCTOR_NO_NETWORK=1` to avoid GitHub API flakiness.

plugin/examples/echo/go.mod

@@ -1,6 +1,6 @@
 module github.com/Cod-e-Codes/marchat/plugins/echo
 
-go 1.21
+go 1.25.9
 
 require github.com/Cod-e-Codes/marchat/plugin/sdk v0.0.0
 

plugin/sdk/go.mod

@@ -1,3 +1,3 @@
 module github.com/Cod-e-Codes/marchat/plugin/sdk
 
-go 1.21 
+go 1.25.9